November 22, 2011
Three Choices for “Dosing” Insulin for Type 2
I have not seen a lot of discussion about this topic. Many bloggers talk about bolusing for covering carbohydrates and for high blood glucose readings, but this blog by Joslin Communications talks about three choices for “dosing” insulin. This is talking about people with type 2 diabetes. Yes, type 1 is mentioned, but mainly as a comparison for helping type 2's get past their fear of needles and insulin.
The article discusses three basic types of regimens for people that use a basal/bolus treatment. The first is known as a fixed dose. The fixed dose regimen is predicated on the assumption that people eat a consistent amount of carbohydrates on a regular basis. They say that this works well and is appropriate for people new to diabetes and their understanding is limited and want to approach change slowly.
While they do describe varying the amount of insulin with each meal, the disadvantage is the rigidity and not allowing for extra insulin if the pre-meal blood glucose is high. This also can create problems if you are not feeling good and are not as hungry, thereby limiting the food intake for that meal or skipping that meal. This is when people on fixed doses of insulin can experience hypoglycemia. This also does not allow food intake to vary greatly and people will end up with a pattern of blood glucose readings that vary widely.
Next, the blog talks about the sliding scale for insulin dosing. I had hopes that this was more informative, but basically it just requires more testing pre-meal and adjusting for insulin as a correction, but using a fixed dose for the meal that will be eaten. This can be especially dangerous if for any reason a meal is delayed or not eaten as hypoglycemia can be a very real problem if this happens.
A sliding scale requires more patient time investment to manage diabetes and maintain a higher level of management. This method is preferred over the fixed dose of insulin and does allow for better management of diabetes if they are committed to a structured meal plan.
Both the fixed dose and sliding scale are based on carbohydrate counting and requiring that the food consumed matches the insulin injected. This means that people can vary the type of foods somewhat, but the total carb count must be the same for each meal.
The third approach in called matching insulin to carbohydrate. This is the method I use and does require knowing two ratios and applying them correctly. It also takes a little time to discover what each ratio is for yourself. Here you will definitely become your own science experiment to determine and refine your insulin to carbohydrate ratio and the correction ratio.
Unless you are extremely knowledgeable and very lucky, this process will take some time. I remember adjusting and refining mine for almost a month and then having a CDE tell me I was not doing it right. Turns out, I was right even if she thought otherwise. I was very insulin resistant and as a result my ratio was very narrow both for the insulin to carbohydrate and correction ratios.
In addition, you need to know what your target blood glucose is when the insulin is done. In my case, I take Novolog and it lasts for about four hours. I know that if I test before my next meal and I am above my target, either I miscalculated my carbs or my insulin resistance has increased or decreased. In addition, other factors can influence the blood glucose readings, such as stress, illness, or other factors. You will soon learn what affects you and how your body chemistry reacts to different factors and before long, you will become very adept at adjusting your ratios.
To use this method requires more attention to detail and good math skills. Insulin to carb matching is worth the extra effort because it allows more flexibility in food choices and most importantly enables you to take a more active role in your care.
Read the Joslin blog here.